1. Field of the Invention
The present invention relates to biomedical electrodes of the type attached to the body and, more particularly, to an adaptive electrical connector which permits a conventional lead wire plus female couple assembly to interconnect a studless electrode by locating an electrode stud on the connector.
2. Background of the Invention
Various configurations exist for electrical conducting connectors such as those used to interconnect electrodes, for example medical or biomedical electrodes, to their corresponding leads and, in turn, monitors. The field is relatively crowded. Designs are usually controlled by, first, a requirement for a secure fastening of the connector to an electrode because the electrode may be part of a life support system. A second requirement of a connector design is controlled by economics: the connector must be easily disposable and replaceable (hence, inexpensively manufactured) to maintain sterility in a medical environment.
Perhaps the most common type of connector simply consists of a quick disconnect, female couple at one end of a lead wire. The couple is designed to hook, snap, or otherwise engage a male stud placed on the electrode to make electrical contact with that electrode. The hook or snap operation of the female couple-stud assembly is advantageous because it gives the operator (e.g., a nurse) affirmative assurance that connection to the electrode has been made; engagement creates a noticeable feel and, typically, an audible sound.
This type of connector is especially desirable for medical electrodes because it allows the electrode to be positioned on the patient and then easily connected or disconnected from its corresponding lead. For that reason, most monitors used by hospitals and clinics incorporate leads which have female couples. Moreover, the quick disconnect capability is advantageous especially for disposable electrodes; such electrodes are discarded after use and a single lead is reused with a number of electrodes. The lead wire plus female couple connector requires, however, that the electrode which it engages have a conductive male stud.
Another common type of connector is able to engage a studless electrode. One example of such a connector includes two, pivotally mounted, spring-biased metal jaws which may have multiple teeth for gripping the electrode: an alligator clip. Another example is disclosed in U.S. Pat. No. 4,702,256 issued to Robinson et al.
The electrical connector disclosed by Robinson et al. offers a unique gripping surface which allows the connector to maintain a good grip on a studless electrode without piercing it. A small, plastic member is provided with an electrical contact mounted in one of its jaws. The contact mates with an angled edge on the opposite jaw of the member to crimp and securely grip a studless electrode in the connector while making good electrical contact.
Still other types of connectors able to engage a studless electrode are disclosed, for example, in U.S. Pat. No. 4,797,125 issued to Malana and U.S. Pat. No. 4,178,052 issued to Ekbom et al.
The electrodes to which these various electrical conducting connectors attach can generally be placed into two categories. In one category are those electrodes which have a male stud. The connector interconnects the "stud-containing" electrode by engaging the stud. An advantage of such an electrode is that it permits rotation between the electrode and the connector. Rotation both assures patient comfort and prevents the electrode from disengaging when the patient moves.
The other type of electrode is usually thin, flat, flexible, disposable, studless, and, therefore, less expensive to manufacture or use. The connector interconnects that second type of electrode by engaging the electrode itself, usually at a lateral extension or tab. Thus, this second type of electrode is referred to as a "tab" electrode.
One problem with the tab electrode is that it typically does not permit rotation between the electrode and the connector. Another problem is that tab electrodes cannot be readily connected to the female couple connector of the type in wide-spread use for making contact with the stud-containing electrodes. Consequently, many hospitals and clinics cannot benefit from the cost savings provided by the tab electrodes.
The general object of the present invention is, therefore, to provide an electrode connector which functions as an adapter and allows such facilities to use the advantageous (e.g., inexpensive) tab-type electrode with their conventional monitor-lead-female couple assemblies--while allowing rotation between the connector and electrode. Such a connector assures that each of the electrodes and connectors described above can be interconnected.
In order to achieve that general object, a more specific object is to place a male stud on the electrically conducting connector. A connector with a male stud eliminates the need for the electrode to carry the stud. Thus, the stud can be removed from the electrode and studless, tab-type electrodes, with all of their benefits--primarily reduced cost both to manufacture and to use--can be applied. Such application is feasible even with conventional lead wire plus female couple connectors and retains an important advantage of the stud-containing electrodes, namely, rotation between the connector and electrode.
Patient comfort is the overriding concern with any electrode and connector design. Accordingly, it is an object of the present invention to assure patient comfort. At the same time, rotational movement between the connector and electrode may be necessary to provide a good electrical connection. Such connection must be assured even when the patient moves. Accordingly, it is another object of the present invention to assure significant rotational movement between the connector and the electrode.
The Lec Tec Corporation has developed one design which removes the male stud from an electrode (see U.S. Pat. No. 4,911,657 issued to Berlin). As with many of the patented devices which remove the stud from the electrode, however, the Lec Tec design requires additional, non-standard, non-disposable, costly equipment. Moreover, it is not adapted to use the standard and conventional lead wire plus female couple assemblies now in widespread use; rather, it replaces those assemblies.
Specifically, the biomedical electrode connector disclosed in the patent has a lead wire with a female couple connector at one end and, adjacent to that connector, a male stud which is secured to the lead wire by a tether. The male stud and female couple are aligned on opposite sides of a tab portion of a tab-type electrode. They establish both a mechanical and an electrical connection to the tab when snapped together through the tab.
The focus of the Lec Tec design is to enable a separate lead wire provided with a female couple connector to be used with tab-type electrodes. The design works best when the electrode has a pre-punched opening in its tab to allow the male and female members of the connector to engage. Absent such an opening, the connector must be forced together to puncture the tab before the male and female members engage. The requirement of force is undesirable. Further objects of the present invention are to avoid the need either for a pre-punched hole in the electrode or the use of force to create a hole in the electrode.
Moreover, the focus of the Lec Tec design on tab-type electrodes makes it less desirable for stud-containing electrodes. When the female member of the connector is used to engage the male stud on the stud-containing electrode, the tethered male member of the connector is unnecessary. It dangles uselessly, therefore, as an undesirable potential obstruction. Another object of the present invention is to avoid potentially obstructing structure.
A further object is to avoid unnecessary replacement of the conventional lead wire plus female couple assemblies connected to most monitors. Consider, for example, a monitor having a conventional assembly interconnected to a first patient with a stud-containing electrode in place. In order to use the Lec Tec design with that monitor for a second patient with a tab-type electrode in place, the conventional assembly must be disconnected and the Lec Tec design inserted into the monitor. In contrast, the present design adapts the conventional assembly for use with the second patient without disconnecting that assembly from the monitor.